Generally, the block belt of this type includes a tension band required for torque transmission, and blocks receiving thrust from a pulley. In such a block belt, reinforcing material made of highly elastic metal such as aluminum alloy is buried in the blocks, and the blocks are molded with resin such as phenol resin, resulting in enhancement of block strength. Thus, the block belt has a structure which resists to lateral pressure from the pulley and allows high load transmission.
The tension band is press-fitted to the plurality of blocks, and therefore a single belt is formed. Thus, while running the belt, a belt temperature is increased due to a compression strain arising from the press-fitting of the tension band and a bending strain arising from bending of the belt, and heat of the belt thermally expands a rubber portion of the tension band. As a result, more heat is generated from the belt. In course of time, elasticity of the tension band has been lost due to permanent deformation of the rubber portion. A portion between each of the blocks and the tension band is loosened, thereby causing a clearance between each of the blocks and the tension band. There is a problem that such a clearance causes an oscillation of the blocks, and increased force input to the blocks damages the blocks.
In order to obtain both of durability and heat resistance, a high load transmission V-belt in which a compression allowance is defined between a block and a tension band has been proposed as described in Patent Document 1.